Scaffold



4 Sheets-Sheet l NVENTOR. Thomas G. 0:1 Santi ATTO kusss Sept. 17, 1946. 1'. G. Dl sANTi SGAFFOLD Filed May 3, `1945 Sept. 17, .1946.` T'. G. DI lSANTI 2,407,655

scAFFoL Filed May 5, 1945 4 Sheets-Sheet 3 K NVE-NTOR. Thomas G. Dl.' Sanft' F BYGLLUJWW'M ATToRNEss Patented Sept. 17, 1946 UNITED STATE s PATENT OFFICE Claims.

1 -This invention relates to scaffolds and refers, more particularly, to adjustable scaifolds which can be used in building operations and for other kinds of work and which are so constructed that the platform of the scaffold can be raised and lowered at will.

An object of the present invention is `the provision of a scaffold which is simple in construction and inexpensive to manufacture and which can be conveniently utilized in building operations of various types.

`Another object is the provision of a scaffold which is reliable and safe in operation and which is so constructed that no serious accidents can be caused by any negligence in operating the scaffold.

Yet another object is a provision of a scaffold which is provided with a continuously operating braking means holding the scaffold, the scaffold being movable only when these means are maintained in a released position.

Still another object is the provision of a conveniently operated locking device which may be used to facilitate continuous movement of the Scaiold.

Other objects of the present invention will become apparent in the course of the following specication.

In accomplishing the objects of the present invention, it was found desirable to provide a scaffold having brake shoes which ,are urged by springs to press continuously against the posts of the scaffold and thereby hold it securely in position. The brakes are released through the manipulation of a lever which can :be locked in an inoperative position through the use of a suitable locking device.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings showing, by way of example, a preferred embodiment of the inventive idea.

In the drawings:

Figure 1 shows a scaffold in front elevation with the brakes in the operative locking position;

Figure 2 is similar to Figure 1 and shows the scaffold with the brakes locked in the inoperative position;

Figure 3 illustrates in front elevation the rope supporting means which are used to operate the scaffold;

Figure 4 is a side view of the device shown in Figure 3;

i 2 Figure 5 is a section along the line 5-5 of Figure 4;

Figure 6 is a section along the lines E-B of Figure 1;

Figure 7 is a section along the lines I-l of Figure 1;

Figure 8 is a detail view illustrating the lever Vwhich operates the brake mechanism.

The scaffold frame shown in the drawings consists of four rigid frameelements B, 9, III, II, attached permanently to two sleeves I2. I3, sliding over two vertical posts I4, I5. Two other posts carry a similar scaffold frame (not shown). The ooring of the scaffold, which is also not shown, extends between the two scaffold frames.

The scaffold frame is prevented from sliding down the vertical rods I4, I5 by two brakes shoes I6, I 'I, made of wear resistant material and in contact with vertical rods i4, l5, through opene ings I8, IB, provided in the sleeves l2, I3. The brakes I 6, I'I are held in position by two bars 2li, 2l having a common swivel joint on pinion 22 in the center of rigid members 8 and Il] at an equidistant point between sleeves I2; I 3. A U-shaped hanger 23 is connected to the frame members 8 and Ill by any suitable means and is used for hooking the block and tackle ropes 'I0 to hoist the scaffold.

It is apparent that the scaffold as a Whole will have a normal tendency to exert pressure upon brakes I6, I'I causing these latter to become wedged firmly against vertical posts I4, I5. The links 20 and 2l are connected 'to the brake shoes I6 and I'l with a certain amount of play. The wedging action is further increased by tension of springs 24, 25 through a system of connecting links 26, 2'! mounted at one end on pinions 28, 29 on brakes I6, Il, and at the other end on pinions 30, 3l in folding arms 32 and 33. Arm 32 has one end fastened to a pinion 34 at the lower end of sleeve I2. The other end of Vertically folding arm 32 is fastened to the end of spring 25. a constant vertical pull upon arm 32. This pull is developed into pressure through the lever formed by the relative position and swinging connections of the link 25 connecting armi 32 to brake IS and'fastened by pinions 28, 3Q. The pressure developed in this lever arrangement in* creases the pressure of brake I 6 against its vertical post I4, thereby firmly holding the scaffold in a stationary position. The upper ends of springs 24, 25 are fastened to the transverse frame element I0. The purpose of these springs is to' exert pressure on the brakes I6, Il, as above Thus the tension of spring 25 exerts p upon arm 32 mounted on pinio-n 34 and arm 33.

mounted on pinion 35.

The transversal supporting beam or frame element II has one of its ends fastened to slidingY sleeve I2, while the other end is fastened to sleeve I3.

Beam II is provided with a pinion 36 upon which fulcrums a lever 3l' carrying a pulley Wheel 38 resting upon the upper edges of folding arms 32, 33 and causing a downward swing of 'these arms. The nose 39 of this lever may rest against a locking bar 5B fastened to a ratchet wheel 45 rotatably mounted on pinion 4I. One end of an arm 42 pivots on pinion 4I, while its other end 43 is pulled vertically upward byspring 44 fastened at point 45 on upper beam or frame I3. This upward motion displaces a pawl 45 mounted on pinion 4l on arm 42 and having a sharp point 48 which engages into a tooth of ratchet wheel 45, thus preventing the counter-clockwise rotation of the ratchet wheel (looking in the direction of Figure l).

A hand or foot operated release lever 43 has the .and which has rounded ends 52 'and 52a of this arm coming intermittently in contact with a concave section 38a at lever 3l'.

The scaiold is hoisted by a block and tackle running from hook23, shown in Figures 1 and 2, to hook 53 in Figure 3, fastened by bolts 53a on a beam 54. The beam 54 slides up or down on the vertical rods I4, I5 and is held in a steady position by clamps 55, 56 which are tightened by screw handles 5l, 53.

As shown in Figure 5, each of the clamps 55 or'55 consists of two semi-circular jaws 59, 5@ fitting closely around rod I5. Jaw Ell is adjusted by turning screw handle 58 and is held in position by two sliding bolts 62 and 53.

The described scaffold is operated as follows: The brakes are unlocked to allow the hoisting or the lowering of this scaffold by pushing down the upper end 43a of control lever 49. The action of the mechanism is as follows: When lever 49 is pushed down along with the lever 3l, the -pulley wheel 38 riding along the upper edges of folding arms 32, 33 will describe a downward curved motion involving pressure of this wheel upon arms 32, 33 and causing these latter to fold downwardly while pulling down link arms 26, 2l' fastened on brakes I6, I "I, thus'causing these brakes to be displaced away from their points of friction on vertical rods I4, I5.

When control lever 49 is released, springs 24, 25 pull up folding arms 20, 2| and arms 32, 33 to their original position. During this motion lever 3l swings downward around its pinion 35 and presses down its concave curved nose 39 on the locking bar 50. Then the brakes I6, I'I are 4 locked and the scaffold is prevented from sliding down the vertical rods I4, I5.

The self wedging action of brakes I6, I'l is an important feature of the present invention enabling the operator to anchor the scaiiold easily and safely at any height desired.

This invention' provides safe, eicient and practical means to enable one person to hoist or lower the novel scaffold herein described with a minimum of efforts and with a maximum ease of control due to the automatic self wedging brake actions involved.

It is apparent that when the lever 49 is swung about the pivot 35 from the locking position shown in Figure 1 to the unlocked position shown in Figure 2, the nose 39 is raised from the bar 50 provided that the bar 5U at that time is in the position shown in Figure l.

Usually the operator will raise Vor lower the scaffold by pulling at the rope 'I3 while holding the lever 4S in its open position through the application of hand or foot pressure.

In certain instances, however, it is desirable t0 maintain the lever 49 in its o-pen position. The bar 53 which is used for this purpose can be conveniently swung into its locked position by pulling at the cord 'Il which is attached to the lever 42 at 43,

If the cord ll is pulled it will cause the lever 42 vto swing about the pivot 4i thereby expanding the spring 44. f

In the coursev of lthis swinging motion the pawl 43 will press against the ratchet wheel 40 and will rotate this wheel along with the bar 50 which is rmly attached thereto.

As a result of this rotation the bar 52 will be moved to position shown in Figure 2 in which the end 52 of the bar 54 is in engagement with the nose 39.

As soon as pressure on the cord 'II is released the spring 44 contracts and will swing the linkV 42 about the pivot 4I Vwhile the pawl 46 will slide over the teeth of the ratchet 43. A spring (not shown) may be used to facilitate the insertion of the pawl 4B into engagement with an adjacent tooth of the ratchet 45.

It is apparent that if pressure upon the outer end of the lever 43 is released at that time', the pressure of the springs 24 and 25 will merely strengthen the engagement of the nose 39 with the bar 50.

In order to release the lever 49 and to cause the brake shoes I6 and Il to press against the posts I4 and I5 it is merely necessary to move the bar 50 out of engagement with the nose 33 in the manner hereinbefore described.

It is apparent that the described scaffold provides a simple and eiectively operating construction by means of which the frame of the scaffold is always maintained in its locked position upon the posts so that there is no danger that accidents may be caused as the result of a negligent operation of the scaffold.

It is furtherV apparent that the illustration shown above has been given solely by way of illustration and not by way of limitation and that the described construction is subject to wide variations and modifications without exceeding the scope or intent of the present invention; all

Vof such variations and modications are to be included within the scope of the present'invention. Y

What is claimed is:

1. In a scaffold, in combination with a post, a

sleeve slidable upon said post, a brake adapted to engage said post, a link having an end pivoted to said brake, an arm pivoted to said sleeve, said link having another end pivoted to said arm intermediate the ends of the arm, a frame element carried by said sleeve, a spring carried by said frame element and connected with said arm for maintaining said brake in engagement with said post, a lever, and means connected with said lever and engaging said arm for releasing pressure upon said brake when said lever is actuated.

2. In a scaffold, in combination with a pair of posts, sleeves slidably mounted upon said posts, at least one upper frame element extending between said sleeves and rmly connected thereto, at least one lower frame element extending between said sleeves and rmly connected thereto, said sleeves having recesses therein, brakes adapted to engage said posts in said recesses, links having ends pivotally connected to said brakes, two arms extending side by side and having opposed endspivotally connected to separate sleeves, said links being pivotally connected to separate arms intermediate the ends of the arms, springs having upper ends connected to said upper frame element and lower ends connected to the other ends of said arms, whereby said brakes are maintained by said Vsprings in engagement with said posts, a lever swingably mounted upon said lower frame element, and a roller carried by said lever and engaging said two arms, said roller depressing said arms to release pressure upon said brakes when said lever is swung.

3. In a scaffold, in combination with a pair of posts and rope-actuated hoisting means thereon, sleeves slidably mounted upon said posts, at least one upper frame element extending between said` sleeves and rmly connected thereto, at least one lower frame element extending between said sleeves and Iirmly connected thereto, said sleeves having recesses therein, brakes adapted to engage said posts in said recesses, a rope-engaging element carried by said upper frame element for hoisting the scaifold, elongated connecting mem- 6 bers having ends pivotally connected to said brakes and other ends pivoted to said upper frame, links having ends pivotally connected to said brakes, two arms extending side by side and nected to the other ends of said arms, wherebyl said brakes are maintained by said springs in engagement with said posts, a lever swingably mounted upon said lower frame element, and a roller carried by said lever and engaging said two arms, said roller depressing said arms to release pressure upon said brakes when said lever is swung. A

4. In a scaffold, in combination with a post, a brake adapted to engage said post, means for pressing said brake against said post, a lever connected with said means and movable to a releasing position for releasing pressure upon said brake, said lever having a free end, a ratchet wheel, a pawl-carrying lever, means supporting said ratchet wheel and said pawl-carrying lever for rotation, a pawl upon said pawl-carrying lever for engagement with said ratchet Wheel to turn the ratchet wheel in onedirection, and a locking bar rmy connected to said ratchet wheel and rotatable therewith to a position wherein it locks said releasing lever in its releasing position.

5. In a scaffold, in combination with a post, a sleeve slidable upon said post, a brake adapted to engage said post, a link having an end pivoted to said brake, an arm pivoted to said sleeve, said link having another end pivoted to said arm intermediate the ends of the arm, spring means connected to said arm for maintaining said brake in engagement with the post, and leverage means in operative connection with said arm for releasing pressure upon said brake when said leverage means is actuated.

THOMAS G. DI SANTI. 

